In each level you must try getting to the highest possible number, like displayed on top of the screen. But you can only get there step by step, by making the next number above the currently highest number. E.g. in level 1 you start with 3 as highest number, and you must get up to 26. But you have to first make the 4, the 5 is a prime number, which you get for free. Then you have to make the 6 and so on until you reach 26. Now you have finished level 1.
You can create a new, higher number by the multiplication of two available numbers from the playing field. Just click one and then another number. The two selected numbers will disappear from the playing field and the product of the two numbers will appear. However you are not allowed to multiply two numbers, if the result was higher than one above the currently highest. Therefore after selecting the first number only those numbers stay selectable, which fulfil this requirement. It may be that not a single number is active, since no valid multiplication is possible.
If you need a specific number for a multiplication, but it is not available on the playing field, you can search for numbers, which have the number you need as a factor. E.g. if you need a 2, but there is only a 6, which actually is 2*3, you can push the \'Split\' button and then select the 6. Now the 6 is split into two factors, 2 and 3, which appear on the playing field, and the 6 is gone. Obviously you can not split prime numbers, so they will be deactivated when you press \'Split\'. And you can not split the currently highest number, because that would be a regression.
If you cant find a suitable number to split, press \'New\'. This will provide you with a new number, which is guaranteed to be a factor of the number you are currently heading for. But don\'t press \'New\' too often, first try finding a suitable number to split. Otherwise your playing field will be cluttered with useless numbers and you won\'t be able to get to the target number for the current level.
Every level has a maximum number of number fields and a highest possible number you can achieve. E.g. level 1 has 9 number fields and you can get up to number 26. Level 2 has 12 number fields and you can get up to number 43, and so on. If you make it to the target number of a level, you can start the next level. Otherwise you can try doing better at the same level.